Create component for showing browser context menu

[pocmo]

In the reference browser we want to show a context menu when long-pressing on web content:

For example:

• As a User I want to be able to long press on any image in web content to open it in a new tab reference-browser#101 (Open Image In New Tab)
• As a User I want to be able to long press on any link in web content to download it reference-browser#100 (Download Link)
• As a User I want to be able to long press on any image in web content to download it reference-browser#104 (Download Image)
• As a User I want to be able to long press on any image in web content to share it to another application reference-browser#103 (Share Image)

It's likely that we want to split this into multiple things:

• A browser-contextmenu component that can show a context menu with dynamic entries (like browser-menu) - with matching concept-contextmenu component.
• A feature-contextmenu component that sets everything up, that can add/customize some standard actions (see feature-awesomebar and providers)

┆Issue is synchronized with this Jira Task

[jonalmeida]

Taking a short stab at what the concept-contextmenu would look like after having worked on the Toolbar (feel free to ignore):

abstract class ContextMenuAction(
    // For an optional icon beside the text
    icon: Drawable? = null,
    // Description of the optional icon
    iconDescription: String? = null,
    // Name of the context menu to display
    label: String,
    // If the context menu should be visible depending on some external factor (e.g. image instead of text)
    visible: () -> Boolean = { true },
    // Click listener
    listener: () -> Unit
) {
    // Maybe this could be a separate interface?
    abstract fun createView(parent: ViewGroup): View
}

Still thinking about the ContextMenu itself.. 🤔

I can see browser apps needing to inflate their own View/ViewGroup/layout (e.g. Focus would want to have a banner at the bottom saying downloads don't get deleted).

interface ContextMenu {
  // When the view is created, do custom view things
  fun createView(parent: ViewGroup): View

  // Set menu actions.
  fun setMenuActions(actions: List<ContextMenuAction>)

  // This is just useful in general.
  fun asView(): View = this as View

  // Handling back presses if no option is selected.
  fun onBackPressed() : Boolean

  // Provide the selected action.
  listener: (ContextMenuAction) -> Unit
}